The correct answer is number 4) the topic of the discussion.
A good thing to settle with a group BEFORE beginning a discussion is the topic of the discussion.
When you call for a meeting the people who are going to participate must be aware of the topic at hand or the motive of the meeting. This helps them to collect the information that is going to be needed, prepare papers, data, statistics that are going to be needed to actively participate in the meeting and be productive.
